At a news conference Monday afternoon, Police Commissioner Richard Dormer said authorities were offering up to a $5,000 reward for information on the suspect, who got away with prescription drugs after the shooting inside Haven Drugs in Medford shortly after 10 a.m. Sunday.

Police are also making a special appeal to doctors and pharmacists in the area to come forward if they may have any leads regarding the suspect. Dormer also issued a word of caution to pharmacies — especially smaller stores — to be extra vigilant.

“We believe the suspect is a drug user and should be considered armed and dangerous,” Dormer said.

Heartache has blanketed the entire community in Medford.

“It’s a huge tragedy to the whole neighborhood,” Paisley Taylor, a customer at the pharmacy, told CBS 2’s Hazel Sanchez. “It’s just so close to home that it makes you wonder how safe you are.”

Authorities said the gunman is white, about 5-foot-8 with a thin build, short dark hair and dark facial hair. He was last seen running east on South Haven Avenue wearing a black backpack.

Police said surveillance cameras captured these images of the suspect in the fatal shooting of four people at a Long Island pharmacy. (Credit: Suffolk County Police)

Police have also released new video surveillance photos, caught by recently installed security cameras.

Calling the shooting “the most heinous, brutal crime Suffolk Police have ever encountered,” Dormer said the victims offered no resistance and were killed quickly and at close range.

Meanwhile, Jennifer Mejia, who worked at the pharmacy, was a high school senior days away from receiving her diploma when she was shot dead, execution-style.